1. Field of the Invention
The present invention relates to concrete screeds. More particularly, the present invention relates to extremely light weight, single operator, portable power vibratory "Wet Screeds" used to smooth and level freshly poured concrete without the use of forms or other devices to ride or rest on. The wet screeds float on the concrete as it tamps and smooths.
2. Description of the Prior Art
Numerous screeds employ vibratory action to tamp and smooth concrete in the final finishing step. U.S. Pat. No. 4,340,351 describes a vibratory concrete screed used in the final finishing of concrete. This screed requires two operators. U.S. Pat. No. 4,641,995 describes a vibratory concrete screed which rides on forms to screed narrow strips of concrete, such as walks. This screed is mounted on the operator via a complicated harness counter-weighted frame and is powered by electricity. As a result, the screed requires electrical power on site and the screed requires manipulation of lengthy extension cords.
Escalating labor costs and the unavailability of qualified concrete helpers have pushed the concrete finishers' profitability margin down continually, thus forcing rising costs of construction nationwide. The current standard method of "Wet Screeding" freshly poured concrete is with a 2" by 4" board 8' to 20' long with one or two men hand working the concrete all day long as two to four laborers, "puddlers", push the fresh concrete, "mud", in place with concrete rakes. The hand process is not only slow, inefficient and labor intensive, it is also often requires the addition of more water to the concrete mix to make it more workable. The additional water reduces the strength of the concrete, causing voids and weak spots. The addition of water to produce slumps of 6" to 8", so the finisher can effectively hand "Wet Screed" the fresh concrete, is common in the industry nationwide today. The hand process limits the finisher to the average pour of 6,000 to a maximum of 8,000 square feet of slab per day for a crew of six.
In view of the shortcomings of hand processing wet concrete and prior vibratory screeds, a need exists for a wet screed which effectively and efficiently prepares wet concrete for use. The present invention provides such a screed.